1. Field of the Invention
The present invention is concerned with a process and a packing machine for manufacturing filled drinking cups closed by cover foil blanks heat-sealed thereto and formed by deepdrawing from a continuous sheet of thermoplastic packing material and comprising a beaded peripheral flange, with the cover foil blanks thereof being provided with a pull flap.
2. Description of Prior Art
Drinking cups of this type comprising beaded peripheral flanges and pull flaps provided on the cover foil blank are known in the art, for example, from British Patent Application No. 2 243 137 A. Drinking cups according to German Utility Model 81 18 904 also are provided with beaded peripheral flanges; however, the cover foil blanks thereof do not contain pull flaps. In both cases, loading and sealing is effected through the cover foil blanks on the finished cup-shaped receptacles, so that also the cover foil blanks along with the flaps according to British Patent Application No. 2243137 can readily be hermetically heat-sealed.
Moreover, German Patent Application No. 39 28 654 A1 describes cup-shaped packages the cover foils of which, it is true, do have a pull flap; however, the peripheral flange of such packages is not downwardly beaded so as to afford comfort to the user's lips. The cover foil blanks, during a cyclical continuous manufacture, are not applied and sealed as individual blanks to the strip of packing material provided with cup-shaped moldings, but a sheet of cover foil is rather applied to the strip of packing material to be circumferentially sealed about the cup openings thereof, whereupon only the flaps will have to be punched from the cover foil sheet without affecting the strip of packing material to be then erected and bent in order to enable the sealed cup-shaped packages to be punched thereafter without affecting the bent pull flaps. Apart from the mechanical efforts required for specifically punching alone the flaps from the cover foil sheet, involving substantial disadvantages as this can only be done against the more or less soft material of the strip of packing material, and for erecting and bending the pull flaps, in this process the cover foil sheet will have to correspond to the full width of the strip of packing material resulting in substantially larger waste compared to premanufactured cover foil blanks to be applied and heat-sealed to the cup flanges as individual parts in accordance with the usual practice employed with drinking cups of the afore-mentioned type.
As the cross-section of the cover foil blanks in the cup-shaped receptacles according to German Patent Application No. 39 28 654 completely covers the peripheral flanges of the cups, the beading thereof cannot be considered either as also the margins of the cover foil blanks heat-sealed thereto would be seized by the bead which, in turn, would affect a smooth withdrawal of the cover foil blanks if drinking therefrom is intended.